MAPK8 and brain injury: The JNK pathway, comprising 3 isoforms (JNK1-3), shows distinct regional distribution within the hippocampus, with JNK3 present throughout hippocampal regions while JNK1 localized specifically to CA3, CA4, and dentate gyrus.[63] This anatomical specificity correlates with functional importance in epileptic brain injury, as demonstrated by JNK1 or JNK3 knockout mice exhibiting remarkable neuroprotection following KA exposure.